I actually just had a VBA2C with a posterior baby, the vaginal birth was completely UNPLANNED ... I went into labour 3 days before my planned c-section. And seeing as it was unplanned baby had to be turned as I was pushing her out (more painful than actually delivering her, I didn't have the epidural just some numbing in my bum area) I don't see why they would have to section you just because the baby is posterior Bella had some heart rate dropping issues (don't know if it was due to positioning or not it was an extremely fast labour) and was born with a slight fever due to the heart rate dropping etc. But she is happy and healthy as can be. I say if your dr/OB is willing to give you a VBAC with a posterior baby go for it.